CM2150 Electronic Control System – 019-017   Engine Coolant Level Sensor

Preparatory Steps

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 WARNING 

Do not remove the pressure cap from a hot engine. Wait until the coolant temperature is below 50°C [120°F] before removing the pressure cap. Heated coolant spray or steam can cause personal injury.
 WARNING 

Coolant is toxic. Keep away from children and pets. If not reused, dispose of in accordance with local environmental regulations.

Remove the radiator cap.

Drain enough coolant from the cooling system to empty the radiator top tank. 008-018 in the ISB Series 6.7L Engines (CM2100 and CM2150 Common Rail Fuel Systems) Service Manual, Bulletin 4021578, or the ISC and ISL CM2150 Service Manual, Bulletin 4021569.

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Initial Check

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Three Wire Sensor OEM Harness and ECM Check


 CAUTION 

Engine coolant level sensor can be damaged when removed. It should not be removed unless it is being replaced. Leave engine coolant level sensor installed during functional test.

Verify there are no fault codes present. If Fault Codes 195, 196,1695, 1696 or any other fault codes are present, troubleshoot the fault codes in section TF.

Inspect the OEM harness and engine coolant level sensor connector pins for the following:

  • Loose connector
  • Corroded pins
  • Bent or broken pins
  • Pushed back or expanded pins
  • Moisture in or on the connector
  • Missing or damaged connector seals
  • Dirt or debris in or on the connector pins
  • Connector shell broken
  • Wire insulation damage
  • Damaged connector locking tab.

Use the following procedure for general inspection techniques. Refer to Procedure 019-361 in Section 19.

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Key OFF then lift up on the locking tab and pull the electrical connectors for the coolant level sensor apart from the OEM harness. With the engine coolant level sensor disconnected from the OEM harness, key ON, wait 30 seconds and check for active Fault Code 195. If Fault Code 195 is not active, there is a problem with either the OEM harness or the ECM. Troubleshoot the OEM harness and the ECM as detailed below.

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With the OEM wiring harness disconnected from the coolant level sensor, place a jumper wire between the engine coolant level sensor SIGNAL pin and the engine coolant level sensor RETURN pin at the engine coolant level sensor connector of the OEM harness. Check for active Fault Code 196. If Fault Code 196 is not active, there is a problem with either the OEM harness or the ECM. Troubleshoot the OEM harness and the ECM as detailed below. If unplugging the sensor causes an active Fault Code 195 and placing a jumper wire between the SIGNAL pin and the RETURN pin on the OEM harness causes an active Fault Code 196, the ECM and OEM harness are both  functioning properly and further troubleshooting for the harness and the ECM can be skipped.

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With the engine coolant level sensor disconnected from the OEM harness, key ON and measure the voltage between the engine coolant level SUPPLY pin and the engine coolant level RETURN pin at the engine coolant level sensor connector of the OEM harness. If this measurement is not between 4.75 to 5.25-VDC, there is a problem with either the OEM harness or the ECM. Troubleshoot the OEM harness and the ECM in the next step.

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Check for continuity in the OEM wiring harness for the engine coolant level sensor SUPPLY, SIGNAL and RETURN wires. Use the following procedure for general resistance measurement techniques. Refer to Procedure 019-360 in section 19.

Repair or replace the OEM harness as needed. Refer to Procedure 019-071 in Section 19.

If the resistance for the engine coolant level sensor SUPPLY, SIGNAL and/or RETURN wires is greater than 10 ohms, repair or replace the OEM wiring harness. Refer to Procedure 019-071 in Section 19.

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Check for a short between the engine coolant level sensor SUPPLY, SIGNAL and RETURN wires and all other wires in the OEM wiring harness. If the resistance measured is less than 100K ohms, repair or replace the OEM wiring harness. Refer to Procedure 019-071 in Section 19.

Call for authorization to replace the ECM. Upon receipt of authorization, replace the ECM. Refer to Procedure 019-031 in Section 19.

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Two Wire Sensor OEM Harness and ECM Check


 CAUTION 

Engine coolant level sensor can be damaged when removed. It should not be removed unless it is being replaced. Leave engine coolant level sensor installed during functional test.

Verify there are no fault codes present. If Fault Codes 195, 196,1695, 1696 or any other fault codes are present, troubleshoot the fault codes in section TF.

Inspect the OEM harness and engine coolant level sensor connector pins for the following:

  • Loose connector
  • Corroded pins
  • Bent or broken pins
  • Pushed back or expanded pins
  • Moisture in or on the connector
  • Missing or damaged connector seals
  • Dirt or debris in or on the connector pins
  • Connector shell broken
  • Wire insulation damage
  • Damaged connector locking tab.

Use the following procedure for general inspection techniques. Refer to Procedure 019-361 in Section 19.

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Check for continuity in the OEM wiring harness for the engine coolant level sensor SUPPLY, SIGNAL and RETURN wires. Use the following procedure for general resistance measurement techniques. Refer to Procedure 019-360 in section 19.

Repair or replace the OEM harness as needed. Refer to Procedure 019-071 in Section 19.

If the resistance for the engine coolant level sensor SUPPLY, SIGNAL and/or RETURN wires is greater than 10 ohms, repair or replace the OEM wiring harness. Refer to Procedure 019-071 in Section 19.

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Check for a short between the engine coolant level sensor SUPPLY, SIGNAL and RETURN wires and all other wires in the OEM wiring harness. If the resistance measured is less than 100K ohms, repair or replace the OEM wiring harness. Refer to Procedure 019-071 in Section 19.

Call for authorization to replace the ECM. Upon receipt of authorization, replace the ECM. Refer to Procedure 019-031 in Section 19.

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Test

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 CAUTION 

Engine coolant level sensor can be damaged when removed. It should not be removed unless it is being replaced. Leave engine coolant level sensor installed during functional test.

First check the function of the ECM and the OEM wiring harness. Reference Three Wire Sensor OEM Harness and ECM or Two Wire Sensor OEM Harness and ECM Check in the Initial Check section of this procedure.

With coolant full (above coolant level sensor, key ON, wait 30 seconds and check for active Fault Codes 197 and/or 2448. If these fault codes become active, a damaged engine coolant level sensor has been detected and needs to be replaced. Reference the Remove and Install sections in this procedure.

Drain the coolant level below the engine coolant level sensor, reference the Preparatory Steps section in this procedure.  Key ON, wait for 60 seconds and check to see if Fault Codes 197 and/or 2448 become active. If Fault Codes 197 and/or 2448 do not become active, a damaged engine coolant level sensor has been detected and needs to be replaced. Reference the Remove and Install sections in this procedure.

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Remove

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Lift up on the locking tab and pull the electrical connectors apart.

Remove the sensor.

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Install

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Install and tighten the new sensor according to the vehicle manufacturer’s procedures.

Push the electrical connectors together until they lock.

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Finishing Steps

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Fill the cooling system. 008-018 in the ISB Series 6.7L Engines (CM2100 and CM2150 Common Rail Fuel Systems) Service Manual, Bulletin 4021578, or the ISC and ISL CM2150 Service Manual, Bulletin 4021569.

Operate the engine and check for leaks.

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Last Modified:  20-Apr-2010